GPencil: New conversion to outline in draw mode

This new option converts the stroke to outline perimeter as soon as is drawn.

If no alternative material is set, the actual material is used.

The algorithm is similar to the new operator in D15664

Reviewed By: pepeland

Differential Revision: https://developer.blender.org/D15738

1 files changed, 75 insertions, 11 deletions

diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index 50651e1919a..7f11ff7ebd5 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -918,6 +918,64 @@ static void gpencil_stroke_unselect(bGPdata *gpd, bGPDstroke *gps)
   }
 }
 
+static bGPDstroke *gpencil_stroke_to_outline(tGPsdata *p, bGPDstroke *gps)
+{
+  bGPDlayer *gpl = p->gpl;
+  RegionView3D *rv3d = p->region->regiondata;
+  Brush *brush = p->brush;
+  BrushGpencilSettings *gpencil_settings = brush->gpencil_settings;
+  MaterialGPencilStyle *gp_style = BKE_gpencil_material_settings(p->ob, gps->mat_nr + 1);
+  const bool is_stroke = ((gp_style->flag & GP_MATERIAL_STROKE_SHOW) != 0);
+
+  if (!is_stroke) {
+    return gps;
+  }
+
+  /* Duplicate the stroke to apply any layer thickness change. */
+  bGPDstroke *gps_duplicate = BKE_gpencil_stroke_duplicate(gps, true, false);
+
+  /* Apply layer thickness change. */
+  gps_duplicate->thickness += gpl->line_change;
+  /* Apply object scale to thickness. */
+  gps_duplicate->thickness *= mat4_to_scale(p->ob->obmat);
+  CLAMP_MIN(gps_duplicate->thickness, 1.0f);
+
+  /* Stroke. */
+  float diff_mat[4][4];
+  unit_m4(diff_mat);
+  bGPDstroke *gps_perimeter = BKE_gpencil_stroke_perimeter_from_view(
+      rv3d, p->gpd, gpl, gps_duplicate, 3, diff_mat);
+  /* Assign material. */
+  if (gpencil_settings->material_alt == NULL) {
+    gps_perimeter->mat_nr = gps->mat_nr;
+  }
+  else {
+    Material *ma = gpencil_settings->material_alt;
+    int mat_idx = BKE_gpencil_material_find_index_by_name_prefix(p->ob, ma->id.name + 2);
+    if (mat_idx > -1) {
+      gps_perimeter->mat_nr = mat_idx;
+    }
+    else {
+      gps_perimeter->mat_nr = gps->mat_nr;
+    }
+  }
+
+  /* Set pressure constant. */
+  bGPDspoint *pt;
+  for (int i = 0; i < gps_perimeter->totpoints; i++) {
+    pt = &gps_perimeter->points[i];
+    pt->pressure = 1.0f;
+  }
+
+  /* Remove original stroke. */
+  BKE_gpencil_free_stroke(gps);
+
+  /* Free Temp stroke. */
+  BKE_gpencil_free_stroke(gps_duplicate);
+
+  return gps_perimeter;
+}
+
 /* make a new stroke from the buffer data */
 static void gpencil_stroke_newfrombuffer(tGPsdata *p)
 {
@@ -1221,6 +1279,23 @@ static void gpencil_stroke_newfrombuffer(tGPsdata *p)
       BKE_gpencil_stroke_simplify_adaptive(gpd, gps, brush->gpencil_settings->simplify_f);
     }
 
+    /* Set material index. */
+    gps->mat_nr = BKE_gpencil_object_material_get_index_from_brush(p->ob, p->brush);
+    if (gps->mat_nr < 0) {
+      if (p->ob->actcol - 1 < 0) {
+        gps->mat_nr = 0;
+      }
+      else {
+        gps->mat_nr = p->ob->actcol - 1;
+      }
+    }
+
+    /* Convert to Outline. */
+    if ((brush->gpencil_settings->flag & GP_BRUSH_GROUP_SETTINGS) &&
+        (brush->gpencil_settings->flag & GP_BRUSH_OUTLINE_STROKE)) {
+      gps = gpencil_stroke_to_outline(p, gps);
+    }
+
     /* reproject to plane (only in 3d space) */
     gpencil_reproject_toplane(p, gps);
     /* change position relative to parent object */
@@ -1235,17 +1310,6 @@ static void gpencil_stroke_newfrombuffer(tGPsdata *p)
     }
   }
 
-  /* Save material index */
-  gps->mat_nr = BKE_gpencil_object_material_get_index_from_brush(p->ob, p->brush);
-  if (gps->mat_nr < 0) {
-    if (p->ob->actcol - 1 < 0) {
-      gps->mat_nr = 0;
-    }
-    else {
-      gps->mat_nr = p->ob->actcol - 1;
-    }
-  }
-
   /* add stroke to frame, usually on tail of the listbase, but if on back is enabled the stroke
    * is added on listbase head because the drawing order is inverse and the head stroke is the
    * first to draw. This is very useful for artist when drawing the background.